drivers/iio/humidity/hdc100x.c

   1 /*
   2  * hdc100x.c - Support for the TI HDC100x temperature + humidity sensors
   3  *
   4  * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/delay.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/i2c.h>
  22
  23 #include <linux/iio/iio.h>
  24 #include <linux/iio/sysfs.h>
  25
  26 #define HDC100X_REG_TEMP                        0x00
  27 #define HDC100X_REG_HUMIDITY                    0x01
  28
  29 #define HDC100X_REG_CONFIG                      0x02
  30 #define HDC100X_REG_CONFIG_HEATER_EN            BIT(13)
  31
  32 struct hdc100x_data {
  33         struct i2c_client *client;
  34         struct mutex lock;
  35         u16 config;
  36
  37         /* integration time of the sensor */
  38         int adc_int_us[2];
  39 };
  40
  41 /* integration time in us */
  42 static const int hdc100x_int_time[][3] = {
  43         { 6350, 3650, 0 },      /* IIO_TEMP channel*/
  44         { 6500, 3850, 2500 },   /* IIO_HUMIDITYRELATIVE channel */
  45 };
  46
  47 /* HDC100X_REG_CONFIG shift and mask values */
  48 static const struct {
  49         int shift;
  50         int mask;
  51 } hdc100x_resolution_shift[2] = {
  52         { /* IIO_TEMP channel */
  53                 .shift = 10,
  54                 .mask = 1
  55         },
  56         { /* IIO_HUMIDITYRELATIVE channel */
  57                 .shift = 8,
  58                 .mask = 3,
  59         },
  60 };
  61
  62 static IIO_CONST_ATTR(temp_integration_time_available,
  63                 "0.00365 0.00635");
  64
  65 static IIO_CONST_ATTR(humidityrelative_integration_time_available,
  66                 "0.0025 0.00385 0.0065");
  67
  68 static IIO_CONST_ATTR(out_current_heater_raw_available,
  69                 "0 1");
  70
  71 static struct attribute *hdc100x_attributes[] = {
  72         &iio_const_attr_temp_integration_time_available.dev_attr.attr,
  73         &iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,
  74         &iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
  75         NULL
  76 };
  77
  78 static struct attribute_group hdc100x_attribute_group = {
  79         .attrs = hdc100x_attributes,
  80 };
  81
  82 static const struct iio_chan_spec hdc100x_channels[] = {
  83         {
  84                 .type = IIO_TEMP,
  85                 .address = HDC100X_REG_TEMP,
  86                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  87                         BIT(IIO_CHAN_INFO_SCALE) |
  88                         BIT(IIO_CHAN_INFO_INT_TIME) |
  89                         BIT(IIO_CHAN_INFO_OFFSET),
  90         },
  91         {
  92                 .type = IIO_HUMIDITYRELATIVE,
  93                 .address = HDC100X_REG_HUMIDITY,
  94                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  95                         BIT(IIO_CHAN_INFO_SCALE) |
  96                         BIT(IIO_CHAN_INFO_INT_TIME)
  97         },
  98         {
  99                 .type = IIO_CURRENT,
 100                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 101                 .extend_name = "heater",
 102                 .output = 1,
 103         },
 104 };
 105
 106 static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
 107 {
 108         int tmp = (~mask & data->config) | val;
 109         int ret;
 110
 111         ret = i2c_smbus_write_word_swapped(data->client,
 112                                                 HDC100X_REG_CONFIG, tmp);
 113         if (!ret)
 114                 data->config = tmp;
 115
 116         return ret;
 117 }
 118
 119 static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)
 120 {
 121         int shift = hdc100x_resolution_shift[chan].shift;
 122         int ret = -EINVAL;
 123         int i;
 124
 125         for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {
 126                 if (val2 && val2 == hdc100x_int_time[chan][i]) {
 127                         ret = hdc100x_update_config(data,
 128                                 hdc100x_resolution_shift[chan].mask << shift,
 129                                 i << shift);
 130                         if (!ret)
 131                                 data->adc_int_us[chan] = val2;
 132                         break;
 133                 }
 134         }
 135
 136         return ret;
 137 }
 138
 139 static int hdc100x_get_measurement(struct hdc100x_data *data,
 140                                    struct iio_chan_spec const *chan)
 141 {
 142         struct i2c_client *client = data->client;
 143         int delay = data->adc_int_us[chan->address];
 144         int ret;
 145         __be16 val;
 146
 147         /* start measurement */
 148         ret = i2c_smbus_write_byte(client, chan->address);
 149         if (ret < 0) {
 150                 dev_err(&client->dev, "cannot start measurement");
 151                 return ret;
 152         }
 153
 154         /* wait for integration time to pass */
 155         usleep_range(delay, delay + 1000);
 156
 157         /* read measurement */
 158         ret = i2c_master_recv(data->client, (char *)&val, sizeof(val));
 159         if (ret < 0) {
 160                 dev_err(&client->dev, "cannot read sensor data\n");
 161                 return ret;
 162         }
 163         return be16_to_cpu(val);
 164 }
 165
 166 static int hdc100x_get_heater_status(struct hdc100x_data *data)
 167 {
 168         return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);
 169 }
 170
 171 static int hdc100x_read_raw(struct iio_dev *indio_dev,
 172                             struct iio_chan_spec const *chan, int *val,
 173                             int *val2, long mask)
 174 {
 175         struct hdc100x_data *data = iio_priv(indio_dev);
 176
 177         switch (mask) {
 178         case IIO_CHAN_INFO_RAW: {
 179                 int ret;
 180
 181                 mutex_lock(&data->lock);
 182                 if (chan->type == IIO_CURRENT) {
 183                         *val = hdc100x_get_heater_status(data);
 184                         ret = IIO_VAL_INT;
 185                 } else {
 186                         ret = hdc100x_get_measurement(data, chan);
 187                         if (ret >= 0) {
 188                                 *val = ret;
 189                                 ret = IIO_VAL_INT;
 190                         }
 191                 }
 192                 mutex_unlock(&data->lock);
 193                 return ret;
 194         }
 195         case IIO_CHAN_INFO_INT_TIME:
 196                 *val = 0;
 197                 *val2 = data->adc_int_us[chan->address];
 198                 return IIO_VAL_INT_PLUS_MICRO;
 199         case IIO_CHAN_INFO_SCALE:
 200                 if (chan->type == IIO_TEMP) {
 201                         *val = 165000;
 202                         *val2 = 65536;
 203                         return IIO_VAL_FRACTIONAL;
 204                 } else {
 205                         *val = 100;
 206                         *val2 = 65536;
 207                         return IIO_VAL_FRACTIONAL;
 208                 }
 209                 break;
 210         case IIO_CHAN_INFO_OFFSET:
 211                 *val = -15887;
 212                 *val2 = 515151;
 213                 return IIO_VAL_INT_PLUS_MICRO;
 214         default:
 215                 return -EINVAL;
 216         }
 217 }
 218
 219 static int hdc100x_write_raw(struct iio_dev *indio_dev,
 220                              struct iio_chan_spec const *chan,
 221                              int val, int val2, long mask)
 222 {
 223         struct hdc100x_data *data = iio_priv(indio_dev);
 224         int ret = -EINVAL;
 225
 226         switch (mask) {
 227         case IIO_CHAN_INFO_INT_TIME:
 228                 if (val != 0)
 229                         return -EINVAL;
 230
 231                 mutex_lock(&data->lock);
 232                 ret = hdc100x_set_it_time(data, chan->address, val2);
 233                 mutex_unlock(&data->lock);
 234                 return ret;
 235         case IIO_CHAN_INFO_RAW:
 236                 if (chan->type != IIO_CURRENT || val2 != 0)
 237                         return -EINVAL;
 238
 239                 mutex_lock(&data->lock);
 240                 ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
 241                                         val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
 242                 mutex_unlock(&data->lock);
 243                 return ret;
 244         default:
 245                 return -EINVAL;
 246         }
 247 }
 248
 249 static const struct iio_info hdc100x_info = {
 250         .read_raw = hdc100x_read_raw,
 251         .write_raw = hdc100x_write_raw,
 252         .attrs = &hdc100x_attribute_group,
 253         .driver_module = THIS_MODULE,
 254 };
 255
 256 static int hdc100x_probe(struct i2c_client *client,
 257                          const struct i2c_device_id *id)
 258 {
 259         struct iio_dev *indio_dev;
 260         struct hdc100x_data *data;
 261
 262         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
 263                                      I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
 264                 return -EOPNOTSUPP;
 265
 266         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 267         if (!indio_dev)
 268                 return -ENOMEM;
 269
 270         data = iio_priv(indio_dev);
 271         i2c_set_clientdata(client, indio_dev);
 272         data->client = client;
 273         mutex_init(&data->lock);
 274
 275         indio_dev->dev.parent = &client->dev;
 276         indio_dev->name = dev_name(&client->dev);
 277         indio_dev->modes = INDIO_DIRECT_MODE;
 278         indio_dev->info = &hdc100x_info;
 279
 280         indio_dev->channels = hdc100x_channels;
 281         indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);
 282
 283         /* be sure we are in a known state */
 284         hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]);
 285         hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]);
 286
 287         return devm_iio_device_register(&client->dev, indio_dev);
 288 }
 289
 290 static const struct i2c_device_id hdc100x_id[] = {
 291         { "hdc100x", 0 },
 292         { }
 293 };
 294 MODULE_DEVICE_TABLE(i2c, hdc100x_id);
 295
 296 static struct i2c_driver hdc100x_driver = {
 297         .driver = {
 298                 .name   = "hdc100x",
 299         },
 300         .probe = hdc100x_probe,
 301         .id_table = hdc100x_id,
 302 };
 303 module_i2c_driver(hdc100x_driver);
 304
 305 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 306 MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver");
 307 MODULE_LICENSE("GPL");